LPFM Advisory Letter #22: Worldcast/Ecreso AiO Series Transmitter - Now certified (second update 6/20/24)

Original Advisory (6/11/2024)

REC Networks is putting out the following advisory to LPFM stations, especially those that have just received or are about to receive their construction permits.

The FCC requires that for the LPFM service, all transmitters used must be lab certified and must have a label that reads FCC ID followed by a group of letters and numbers affixed to the unit.  Units that are not lab certified, but are either "type accepted", "type approved", "type verified" or "Supplier's Declaration of Conformity" are not legal for use on LPFM stations as they do not have an FCC ID number.  Past enforcement action against LPFM stations using uncertified transmitters has taken place.  

REC has been advised from Worldcast that the lab certification process for the AiO transmitter series has been delayed and as of June 11, 2024, the model series is not certified and therefore is not legal for the LPFM service.

REC is aware of banner ads that have appeared through various sources promoting this as an "LPFM" transmitter.  Until we receive notice of certification and we have been able to verify the certification, we are advising LPFM stations, grantees and others planning to use this model at an LPFM station to temporarily hold off until the issues with the lab certification can be resolved or if you do decide to purchase now, please wait until certification is completed and you have the label before putting the transmitter on the air.

Our discussions with Worldcast on this issue started earlier this year prior to the NABSHOW in mid-April.  

REC understands the issues that Worldcast is facing and we have called on them to pull all advertising claiming that the AiO series is an LPFM transmitter until we can verify certification. 

Once we verify certification on the AiO series, we will update this Advisory Letter.

For a list of transmitters already certified for LPFM stations, see

First Update (6/12/2024)

Worldcast Systems has released the following press statement:

We would like to address recent concerns regarding the FCC certification process for our 100W and 300W Ecreso FM AiO Series transmitters.

First and foremost, we want to reassure our valued customers that there are no technical issues or concerns with these products. The physical performance of the AiO series has tested exceptionally well, and our current focus is on completing the administrative and paperwork process required for certification.

Second, the certification process is only required for transmitters used by broadcasters holding an LPFM license in the US. This is a very specific type of license, with specific requirements and limitations. All other broadcasters with standard broadcast station, translator, or booster licenses may select from any of the full range of Ecreso transmitters.

We acknowledge that this process is taking longer than initially anticipated, and we sincerely apologize for any inconvenience this delay may have caused. We are actively making the final requested revisions to the documentation and expect to have the certification finalized within a matter of days.

In the meantime, we remain committed to supporting our customers. We can honor purchase orders for the 100W and 300W Ecreso FM AiO Series transmitters as long as the radio station can delay the start of broadcast operations until notification that certification has been granted.

Customers who have already purchased these transmitters will receive an FCC ID sticker to apply once certification is complete.

For any customer facing an urgent need, if certification is not achieved by their required deadline, we offer the option to return their AiO transmitter. Alternatively, we can provide a loaner certified EFM 300 transmitter to ensure they can get on the air without delay.

We apologize once again for the delay in the certification process and appreciate your patience and understanding. Our team is working diligently to finalize this process and deliver fully certified, high-quality transmitters to our LPFM customers.

Thank you for your continued support.

Christophe Poulain President, WorldCast Systems INC

(end of statement)

Again, REC will announce once we have verified that the AiO Series transmitters have received their certification and as noted by the Worldcast statement, those who have already ordered AiO transmitters that shipped or will be shipped without the label can request a label once certification has been achieved.  We note that new LPFM stations have three years to build and if your station has already ordered the AiO, you may have to wait a few extra days or weeks before going on the air.  You still have plenty of time.  I know a lot of you are excited to get on the air.  Good things come to those who wait.  I expect Worldcast to have this situation resolved in the next few weeks so not all is lost here.  Please be patient.  REC is working closely with Worldcast to help bring this new transmitter choice to the LPFM market.  One of my goals during my yearly trips to NABSHOW is to work with transmitter manufacturers to assure that their new models have certification so they can compete in the LPFM market. REC wishes Worldcast the best in completing the certification process and being able to bring this model to market.

Second update (6/20/2024)

WorldCast has contacted REC Networks and we have verified through independent sources that the AiO Series transmitters (100 and 300 watt models) are now fully certified and are permitted for use on LPFM stations.  Their FCC ID number is O35-AIO0300W, which covers both models. 

We recind our previous advice to "hold off" considering now that the equipment is now certified.

LPFM stations that have already received a transmitter without a label should contact WorldCast for assistance. 

REC thanks WorldCast for their extra efforts in order to provide more competitive choices in the LPFM market for transmitter choices. This issue appears to be resolved and this should be the last update on this issue.

For more information on this transmitter, visit the WorldCast Systems website at:

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Revision log

First update 6-12-2024 to reflect the press statement from Worldcast Systems.  We have also revised our original statement to clarify that LPFMs should "hold off" but if they purchase now, they need to wait until they have a label, which will be provided by Worldcast before going on the air.

Second update 6-20-2024 to reflect the verification of the FCC ID number for the Worldcast Ecreso AiO series transmitter and confirming that it can be used on LPFM stations in accordance with FCC regulations.